Piston



D. B. CRAWFORD.

FISTON.

AFE-LiCATlON .FILED AUG. 16. 1920.

1,416,795. Patened May 23, 1922.

2 SHEETS-SHEET l.

@md/@mq D., B. CRAWFORD.

PISTON.

APPLicATxoN FILED AUG. 16, 1920.

I mieres.

, engine.

Down is. CRAWFORD,

or cercado, rumors,

' l PISTON.

` j Specication of Letters Patent. I Pailgmtgqgd May 23',

vApplication filed August 16, 1920. Serial No. 403,784. I

T 0 all lwhom t may concern .i r

a'citiz'en .of the United States, residin vat Chicago, in the county ofCook and tate ofllllin'ois, have invented a new and useful. 'Improvementin Pistons, of which the following is a specification.

This inventionv has relation to an internal combustion engine, andrefers particularly to a novel\ piston construction 4for such Theprimary object of myinvention is the -provision of an improved pistonstructure.,

More 'particularly 4my object is to introduce' resilient devicesoperating to increase the etliciency of the piston by urging the pistonrings against the wall of thecylinder-- vTo this end my inventionconsists in the combinations and advantageous features hereinafter fullydescribedV and illustratedV in the accompanying drawings, 4of which:

Fig. 1 illustrates, in side elevation, a piston structure embodying theinvention,

Fig. 2 is a plan view substantially in agreement with Fig. 1,A y

Fig. 3 is a fragmentary view, on a large scale, illustrating portionsofthe preceding figures,- Y

Fig. 4 shows the resilient' devic's removed from the piston, f Y

. Figs. 5 and 6 illustrate a modified form `of the inventionand Figs. 7and 8 show further modifications the importance of whichwill`h/ereinafter appear. Referring in the rst instance to Figs. 1,2-and 3,7 the numeral 1 denotes. a piston having a plurality ofperipheral grooves 1, in which are seated a correspondlngnumber ofpiston rings 2. The latter may be of any well known constructlon and, ofcourse the more perfectly the ends of the rings are joined together, theless also the leakagev pastv the joints of the rings. 'f ,Within thepiston is placed av sleeve 3 providedmwith `a plurality -of radiallyAdisposed sockets 3a,

Y in which are seated a corresponding number of springs 4., It isnoticed that a corresponding number of perforations lb are provided inthe grooves of the piston, and the sleeve 3 is so placed withinthepiston that said'perforations register with the sockets 3a.yvSlidably mounted in each perforation is a plunger 5 urged lforward bythepressure of the springs 4, and a disc may conveniently be' placedbetween the spring and plunger, orv

hsaid. spring and plunger may beinade in one piece, if desired. Theadvantage of the separate disc and plunger 4is that less accuracy isrequired in positioning the sleevel relative to the perforations in thepiston wall. .0n the other hand there is a distinct advantageincombining the parts, in that it yretains the plungers in place whenythepiston` ring is removed.

It is readilyfseen by anyone versed in the art that the springs t exertpressure against the inner periphery lofthe piston ringsfQ,

thereby urging the latter outwardl in orderv itselfcombined with theexpansion of said ring causedl by the heat generated within thecylinder. lf the ring is too loose a decided waste of fuel ensues, iftoo tight the friction created operates to reduce the power output,besides` scoring and unduly wearing thewalls ofthe cylinder. While inthecommon. type of piston rring great care must bey exercised to vselectthe 'proper material, I wish it understoodthat, in the structure of myinvention, the material best adapted for reducing frictionV between theringand cylinder'wall may be adopted without pay- 9'0 ing. attention tothe aforenamed conditions.

Thisis a very important feature of my invention.

The springs elaibeing` housed within the sockets of the sleeve 3,' arevprotectedfrom flame and dirt. It is, however, desirable' that somesmall opening be provided, such as the perforations 3", through whichthe 'splashing oil. may penetrate and thereby lubricate said springs.4 Ihave hereinbefore spoken of the sleeve as having one row of springsockets operating up'on 'one piston ring,'in which case one sleeveisrequired for each ring employed, but I wish it understood that onecommon sleeve `may be used,` said sleeve having sockets for registrationwith the `whole group 'of piston rings, if'desired.

The l' sleeve structure hereinbefore describedis desirable on accountofthe easewith which it vmay be assembled and put ture for the reasonthat some pistons are `12. The spring sockets in this case, as bestshown in Fig'. 6,- comprise a body portion 13 provided withdiametrically opposite prongs 13a, which in turn are seated inperforations 10c of the piston. It is noticed that the ends l of saidprongs are' riveted over in .order to retain the sockets firmly vinplace, but, ot' course, ay spot Welding or similar operation may beresorted to for this" purpose. The

ysprings 14 and discs 1'5 remain as described, ,and I wish to point out,that the plunger and'di'sc also in this case may be combined into onepiece, if preferred.

The structure of Fig. 8 corresponds in a general Way with the one justdescribed.

.Specifically it is modified by eliminating the plunger elemententirely. In this case the perforations 20 of the piston Wall are madelarge enough tol accommodate the body portion of the sockets 21, and thelatter, as best shown in Fig. 8, are'made Witha {iange 21, which in turnis recessed into a seat in `the piston, in order that the face of'saidsocket may be flush with thel outer piston Wall. It is clearly shown howthe disc 22 is urged by the spring 24: against the piston ring 23.Attention is called to a second series of sockets 25, said socketspositioned to register With the adjacent piston ring (not shown) and itis seen that the sockets 21 and the sockets 25 are placed in staggeredvrelation, which is done in order vto retain the piston Wall as strong aspossi- The devices hereinbefore describedillustrate plainly the scope ofmy invention, but the proportions and relations of the parts may, ofcourse," be varied to suit conditions and in order to obtain thestrongest and most )eiicient structure under the circumstances.

Also the number of spring sockets may be varied to suit individualconditions.

I claim: Y

. 1. The combination With the piston of an internal combustion engineand a piston ring, of means attachable to the piston for holding aplurality of spring-held plungers, said plungers confined Within thepiston when the device is assembled and extending through the pistonWall in order to exert pressure against said pistonv ring.

2. The combination With a piston, provided With a series of radialperforations, and a piston ring'seated in said piston, of a sleevecarrying a series of spring-held plungers seatable in saidperforations,said sleeve insertable Within the piston when `the plungers aredepressed, but'incapable of detachment when said plungers have enteredthe said piston perforations.

B. In the piston of an internal combustion engine, -a sleeve structuremounted Within said piston and having resilient members for urging therings of the piston against the inner Wall of the engine cylinder. l

4:.A In the piston of an internal combustion engine, said pistonprovided with a series of radial perforations, the combination with thepiston rings, of a sleeve fitted Within the piston, said sleeveperforatedto receive a corresponding series of plungers seated in saidperforations,`resilient members urging said plungers against the innerperiphery of said piston rings, and devices for maintaining saidresilient members in position.

5.A In a piston for an internal combustion engine, a sleeve fitting theinner Wall of said piston and provided with series of staggered housingsregistering with perforations of the piston Wall, springs within saidhousings, plungers in said perforations and abutting the rings of thepiston, and discs between said plungers and springs,

`said discs of larger diameter than the plungers in order to allow forinaccuracies of placing the parts.

In testimony whereof I have hereunto af iXed my signature.

DOLPH B. CRAWFORD.

